1. Field of the Invention
The present invention relates to a venous reservoir bag and more particularly to a soft sided or soft shell reservoir that can hold a selectively variable amount of blood and which has a unique and advantageous shape.
2. Description of the Related Art
A venous reservoir bag is typically included in a cardiopulmonary bypass circuit to accommodate for variations in blood volume when cardiopulmonary bypass flow is connected through a membrane oxygenator and to separate the bubbles from the venous blood and to vent such separated gas to atmosphere. Conventional reservoir bags have a blood inlet and a blood outlet defined to extend into the bag from a bottom edge thereof and one or more air vents provided at the apex of the bag. When blood flows into the bag from the inlet and passes through the bag to the outlet, gas bubbles rise to the surface of the fluid in the reservoir and may be vented to atmosphere through the upper vent.
Prior art reservoirs of the type described above generally do not remove all gas bubbles from the blood, particularly if there is a low liquid volume in the bag and/or there are high blood flow rates through the reservoir.